/*
 * Copyright 2014 Facebook, Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#pragma once

#include <boost/noncopyable.hpp>
#include <functional>

namespace folly { namespace wangle {
  typedef std::function<void()> Func;

  /// An Executor accepts units of work with add(), which should be
  /// threadsafe.
  class Executor : boost::noncopyable {
   public:
    virtual ~Executor() = default;

    /// Enqueue a function to executed by this executor. This and all
    /// variants must be threadsafe.
    virtual void add(Func) = 0;

    /// A convenience function for shared_ptr to legacy functors.
    ///
    /// Sometimes you have a functor that is move-only, and therefore can't be
    /// converted to a std::function (e.g. std::packaged_task). In that case,
    /// wrap it in a shared_ptr (or maybe folly::MoveWrapper) and use this.
    template <class P>
    void addPtr(P fn) {
      this->add([fn]() mutable { (*fn)(); });
    }
  };
}}
